Jewish Calendar

The jewish calendar – both sun and moon are included

The Jewish calendar is especially fascinating because it takes into consideration the solar year as well as the lunar year.

Let me explain that:

There are two ways you can measure one year by looking up to the sky:

1. A solar year – the time it takes earth to complete a full circle around the sun. This takes approximately 365 days.

2. A lunar year – the time it takes the moon to complete a full circle around earth [=one month] – times 12. A full circle of the moon takes approximately 29 days and a half. So a lunar year has 354 days.

There are calendars that are based on solar year only. These calendars take the full solar year and divide it to 12 months.

The advantage of using a solar calendar is that the months match the seasons every year.

For example – in the Gregorian calendar – October will always come out in the fall, while July will always come out in the summer [so it’s on the northern part of earth].

The disadvantage of a solar calendar is that the month period gets no expression in nature.Nothing special happens in the world on the first day of a specific month.

There are calendars that are based on the lunar year only.The advantage – there is an astronomical meaning to a month. The month begins when the moon is first seen.

The disadvantage of using the lunar year only is that the seasons are not synchronized with the calendar. That is because the seasons have to do with the location of earth relatively to the sun.

What happens is that every year the calendar “moves back” 11 days. 11 days is the difference between the solar year and the lunar year.

3 years go by – and the calendar “moved back” more than a month!

8-9 years went by – and the calendar is a whole season behind.

I’ll give you an example: The Islamic calendar is a lunar calendar.

Ramadan is a month where Muslims are required to abstain from eating and drinking any liquid during the daylight hours.

This month can come out in the summer. 8-9 years later in the spring, and 8-9 years later in the winter, even though day time in the summer is much longer.

As I started – the Jewish calendar combines the solar calendar and the lunar calendar.

How?

The Jewish months go by the lunar calendar. When the moon is first seen– that is the sign that the month begins.

So where does the solar calendar come in?

There is a special Jewish law which says that Passover must come out in the spring.

How do you do that if you go according to a lunar calendar?

This is the reason for an extra month in the Jewish calendar that appears every two-three years.

The month of Adar is duplicated, right before the month of Nisan – where Passover takes place.

Why does that happen every two-three years? Because – as explained – the gap between the lunar calendar and the solar one is 11 days. Three years go by – and we’re up to a 33 day gap.

More than a whole month!

We sure have to add another month.

But because the gap is bigger than one month – the correction is needed sometimes after two years only.